Cherry Audio released Pentaphonic this month, a plugin emulation of the rare 1981 Gleeman Pentaphonic polysynth. According to Synth Anatomy's review, it costs 59 dollars, ships in VST, VST3, AU and AAX formats for macOS and Windows, and lets you assign modulation to velocity, channel and polyphonic aftertouch. The review does not mention MPE, so this guide focuses on what you can reliably do: use per-note pressure to bring a classic polysynth sound to life.
Why pressure matters on a vintage design
Original polysynths were built for static chords. Their charm comes from drifting oscillators and chunky filters, but a held pad can feel flat. Adding pressure-controlled modulation changes that. Press a little harder on one note in a chord and its brightness or vibrato opens up while the others stay put. That is the essence of expressive playing, and polyphonic aftertouch delivers a good part of it.
Step 1: Check what your controller sends
Before you touch the plugin, confirm what your hardware outputs.
- A keyboard with polyphonic aftertouch sends pressure per key on one channel.
- An MPE controller sends pressure per note on separate channels. Many allow a single-channel mode with channel aftertouch or polyphonic aftertouch.
- A keyboard with only channel aftertouch applies one pressure value to every held note.
Your DAW's MIDI monitor will show exactly which messages arrive. Spend two minutes here and the rest of the setup becomes simple.
Step 2: Assign pressure as a modulation source
Open Pentaphonic's modulation options and look for polyphonic aftertouch as a source. Route it to one destination at first, such as filter cutoff. Set a moderate amount, then play a four-note chord while pressing one key harder. If only that note brightens, polyphonic aftertouch is working. If every note changes together, your controller is sending channel aftertouch instead, so adjust the controller setting.
Step 3: Layer a second destination
Once the first mapping feels right, add a subtle second destination. Good candidates are:
- LFO depth for vibrato that blooms under pressure
- Oscillator detune for a gentle chorus-like swell
- Amplitude for a soft swell on sustained notes
Keep amounts small. Pressure is a continuous control, and small settings feel more musical than dramatic ones.
Step 4: Use velocity and channel sources too
Because the plugin also accepts velocity and channel as sources, you can build a layered response. Let velocity set the initial brightness, and polyphonic aftertouch push it further while the note sustains. That combination mimics how acoustic instruments behave, with a strong attack followed by an expressive tail.
Step 5: Save and test
Store your patch with a clear name such as "Pad - Poly Pressure." Test it at different dynamic levels, and with a sustain pedal engaged, since held notes are where pressure shows its value. If your controller is MPE, remember that per-note pitch bend and slide will only matter if the plugin explicitly supports them, so verify that in Cherry Audio's documentation at cherryaudio.com.
Troubleshooting
- No response to pressure: confirm your controller is sending polyphonic aftertouch and that your DAW is not filtering it.
- Everything moves together: switch the source from channel to polyphonic aftertouch, or change your controller's output mode.
- Too jumpy: reduce the modulation amount or smooth the controller's pressure curve.
Final thoughts
A 59 dollar plugin will not turn a keyboard into an MPE controller, but it shows how much expression can come from a single well-chosen modulation source. If you want to go further, pair this approach with an MPE-native instrument and compare how pitch bend and slide extend the same ideas. For the specification behind per-note expression, see the MIDI Association.